To find Barcode fonts a good source would be to do a Google Search for:
barcode font download
However it has already been mentioned that there are a wide variety of Barcodes - some of them 1-dimensional (straight line codes like Code 3 of 9, Interleave 2 of 5, UPC-A, etc.) and some of them are 2-dimensional (square codes like QRCodes, Datamatrix, etc.)
And, again as was mentioned above, some of them are derived simply with a Font and others are the result of a more complicated process.
You first need to determine what Barcode Symbology you are wanting to use (again, Code 3 of 9, I2 of 5, QRCode, Datamatrix, etc.)
Then you can go forward towards implementing the appropriate method of deriving them.
BTW: this forum has a forum area for:
Bar coding Forum
forum694
It won't get into how to incorporate them into your specific ASP.NET code, but it is where people generally discuss the basics.
Good Luck,
JRB-Bldr